By 1980, the number of Americans greater than 60 years of age had increased to 35.6 million or 15.7% of the population. More than 50% of this group are females; virtually all are post menopausal and suffer from osteoporosis to one degree or another. The long term objective of this work is to develop a non-invasive treatment modality than can be used to treat osteoporosis or that can be used prophylactically to prevent the onset of osteoporosis. The aim of this study is to demonstrate the feasibility of utilizing resonant electromagnetic fields to stimulate osteogenesis and thereby reverse the effects of osteoporosis. Osteoporosis will be produced in the rat by unilateral sciatic denervation. After the disuse osteoporosis manifests itself (28 days post denervation) animals will be placed in aligned dc and ac magnetic field for a period of 42 days. The conditions on the field will be set to stimulate the transport across cell membranes of specific ion species and combinations of ion species. A control group will receive the same handling but will be placed within an inactive field condition. In order to evaluate the osteogenic potential resonant electromagnetic field treatment the wet weight, dry weight, ashed weight, ultimate strength cortical area, cortical thickness and cortical porosity of the femora an tibiae will be evaluated in the treated groups as compared to the untreated control.